Switching device



Jan. 16, 1923o 1,442,443 J. B. RADFORD.

SwlTcHlNG DavlcE. FILED JUNE 16, 1920. 2 SHEETS-SHEET l lll //7 VCO/7 for:

Patented Jan. 16, 1923.

UNITED STATES i y c 1,442,443 PATENT OFFICE.

JOHN BODEN `RADEORD, OE vALO1s, QUEBEC, CANADA, AssIoNOR TO WESTERN ELEC- TRIC COMPANY, INCORPORATED, or NEW YORK, N. Y., A CORPORATION Or NEW YORK.

SWITCHING DEVICE.

Application Med June 16,

To all 'whom it may concern.'

Be it known that I, JOHN BODEN RADFORD, a subject of the King of Great Britain, residing at 45 Queens Road, Valois, in the Province of Quebec and Dominion of Canada, have invented certain new and useful Improvements in Switching Devices, of which the following is a full, clear, concise, and eXact description.

This invention relates to electrical switching devices.

The object ofthe invention is to provide an improved switching device for use in normally closed circuits which shall be simple in construction and positive in its operation.

The invention is particularly adaptable in main line circuits in which there are a plurality of local circuits connected in series with these main line circuits.

The invention in its preferred form, provides a plug switch which is ada ted to be inserted in an outlet switch box. (conductive means are provided on the plug to connect` line terminals with local circuit terminals.A The switch box is provided with spring members which, when the plug is removed, contact to connect the line terminals. These spring members are separated by cooperating members attached to the plug. Means is also provided in the plug whereby, when the line voltage exceeds a certain predetermined maximum, the circuit is reestablished across the line terminals to short circuit the local circuit.

The invention will be better understood by reference to the drawings. Fig. 1 represents a front view of the terminal box with the plug removed and portions of the cover cut away; Fig. 2 shows a cross section of the box along the plane indicated by the reference character 2; Fig. 3, shows a cross sectional view at the plane 3, of the box with the plug removed; Fig. 4, shows a bottom view of the plug, and Fig. 5 discloses a circuit wherein the terminal box and plug may be used to advantage. Like reference characters refer to like parts in the various figures. i,

A terminal box 1, made of insulating material is provided with terminal lugs 4. 5, 6 and 7 mounted in the interior thereof, which terminal lugs are secured to conductive bars 8, 9, 10 and 11 respectively, by means of the screws 12. The bars 8, 9, 10 and 11 are fastened to the frame of the box 1 by means of screws 13. Cables 14 and 15 1920. Serial No. 389,279.

enter the box 1 through Openings in the bottom thereof and are attached to the bars 8 and 9 respectively by means of lugs 16 and 17. Cables 14 and 15 may be entered into the box 1 in any suitable manner. In the preferred form the are shown entering through short lengtliis of pipe 18 screwed into the frame of the box 1. The voids between the cable and the box 1 are filled by a quantity of insulating cement 19 which is introduced through an aperture 20. The aperture 2O is thereafter filled by a screw plug 21. Conductors 22 and 23 are attached to the bars 11 and 10 respectivelv in a manner similar to that in which cables 14 and 15 are attached to bars 8 and 9. Terminal lugs 4, 5, 6 and 7 are formed of bent, flat, springy material and in such a form that th#w are adapted to receive a flat conductor bar into their jaws'. The two spring members 24 are fastened under terminal lugs`4 and 5 and bent in such a manner that they present a good flat conductive surface to each other.

It, will thusvbe seen that normally the cables 14 and 15 are electrically connected by the springs 24. A plug comprising a base 25, of suitable insulating material, supports the two bars 26 and27 on projections 28. These bars 26 and 27 are adapted to connect terminal lugs 5 and 6 and lugs 7 and 8 respectively when the plug is inserted into the box 1. Two spring members 29, 'are also supported by the projections 28 on the base 25, and are bent so as to meet midway between the bars 26 and 27 and present to each other a good fiat conductive surface. Between the opposing faces of the spring members 29 is placed a thin sheet of dielectric material 30 which normally serves to prevent the passage of current across the spring members 29. The opposing ends of the springs 29 are adapted to fit between the opposing faces of the spring 24 when the plug is inserted in the box 1 thereby breaking the contact between spring members 24.

When the plug is inserted into the termi' vided to ft-A into the aperture of the box 1 and is fastened thereto by means of bolts 33. The face plate 32, is provided with an outwardly threaded portion 34 onto which is screwed a cover 35 to enclose the box.

- In the circuit shown in Fig. 5, lamps 39, 40 and 4l, are adapted to be connected in series in thevcircuit of which 37 and -38 are the main line conductors. The lamps 39 and 41 complete the circuit through the terminal boxes 42 and 44. Lamp 40, however, bein removed as shown, the plug of the terminal box 43 is also removed and the cir-k cuit is closed through the springs 36. Should the voltage in the main line become excessive, the dielectric material 30 would be broken down and the circuit completed through spring members 24 thus protecting the lamp 39 from damage.

What is claimed is:

1. In an electrical switching device, a pair l of line terminals, a pair of local circuit terminals, a pair of conductive spring members to connect the line terminals, a plug switch comprising members for connecting the line terminals with the local circuit terminals, and an arm electrically connected with each of said members and separated by dielectric material and adapted to be inserted between the pair of conductive spring members.

l2. ln an electrical' switching device,I a pair of line terminals, a pair of local circuit terminals, a pair of conductive spring members to connect the line terminals, and a plug switch comprising a pair of conductive bars to connect the line terminals with the local circuit terminals and a spring member mounted with each said conductive bar, separated from each other by a sheet of dielectric material and adapted to be inserted between the rst pair of spring members.

3. An electrical switching device comprising a casing 'provided 'with a plurality of holes in the top and bottom for the intro- 45 duction of conductor wires and an orifice in the front thereof, a pair of4 line terminals and a pair of local circuit terminals disposed'within the casing, a `pair of spring conductors mounted with the line terminals and normally engaging each other to electrically connect them, a plug. member comprising a base to fit into the orifice in the front of the casing, a pair of conducting bars to connect the line and local circuit terminals, and a member mountedwith each said conducting bar and separated from each other by dielectric material and adapted to be inserted between the first said spring conductors, and a cover for the oritice and the plug.

4. An electrical switching device, comprising a casing provided with a plurality vof holes in the top and bottom for the in traduction of conductor wires, and av circular orifice in the front thereof; a pair of `line terminals and a pair of local circuit terminals disposed within the casing; a pair of spring conductors mounted with the line terminals and normally engaging each other to electrically connect them; a plug member comprising a circular base to fit into the orifice in the front of the casing, a pair of conductive bars to connect the line terminals with the local circuit terminals, and a spring member mounted with each said conductive bar, separated from each other by a sheet of dielectric material and adapted to be inserted between the first said spring conductors; and a screw cover closing the orifice and-covering the plug.

In witness whereof, I hereunto subscribe my 1name this eighteenth day of April, A. D. 192

JUHN BUDEN RADFORD. 

